New headers for C-4's
Le Mans Master
Joined: Dec 2002
Posts: 5,270
Likes: 3
From: Seattle Area WA
way to go guys! Corvette40 were you the guinea pig? DynoDon and TransAm have done some very impressive stuff ahead of the tpi curve. This will be an excellent option especially for those street cars in California.
(p.s. yes these are shorties... however the current offering of shorties is about on par with the lt1 manifolds, yes that is for l98s too, but based on the f body results these do really well considering the design doesn't go full LT. Can't wait for the dyno results! This reminds me I need to go check at thirdgen, haven't been there in a while.)
(p.s. yes these are shorties... however the current offering of shorties is about on par with the lt1 manifolds, yes that is for l98s too, but based on the f body results these do really well considering the design doesn't go full LT. Can't wait for the dyno results! This reminds me I need to go check at thirdgen, haven't been there in a while.)
Thread Starter
Racer
Joined: Jun 2006
Posts: 361
Likes: 6
way to go guys! Corvette40 were you the guinea pig? DynoDon and TransAm have done some very impressive stuff ahead of the tpi curve. This will be an excellent option especially for those street cars in California.
(p.s. yes these are shorties... however the current offering of shorties is about on par with the lt1 manifolds, yes that is for l98s too, but based on the f body results these do really well considering the design doesn't go full LT. Can't wait for the dyno results! This reminds me I need to go check at thirdgen, haven't been there in a while.)
(p.s. yes these are shorties... however the current offering of shorties is about on par with the lt1 manifolds, yes that is for l98s too, but based on the f body results these do really well considering the design doesn't go full LT. Can't wait for the dyno results! This reminds me I need to go check at thirdgen, haven't been there in a while.)
Don and TransAm will finish the install of TransAm's new engine tomorrow, its a beast and I'm sure TransAm will post the dyno results next weekend, then I will install the headers. They won't have the air tubes and will not be coated, those will be the second set I should have next week, but I will post pics when finished.
Last edited by Corvette40; Nov 13, 2011 at 10:27 PM.
Drifting
Joined: May 2006
Posts: 1,428
Likes: 7
From: Chewelah Wa
I have followed these guys on Thirdgen for a long time. If these come in at a reasonable price, they will go on my car. They have to be a big improvement over the stock ones. Especially if you plan on a head upgrade.
Drifting
Joined: Dec 2007
Posts: 1,647
Likes: 4
From: Argillite KY
Figures don't lie.....well, not too much anyways. These headers should make a difference and I would think especially at higher RPM. At lower RPM levels 1000-4000 I would have to think that the long tubes would have a pretty good advantage. From 3500 on up the shorties will come into their element. I don't believe they will match the long tubes but they will come closer. The bigger tube shorties are going to move the torque peak higher and take a hit down low. Think of the relatively short headers on a fuel dragster.
These are a great way to increase power while appearing stock to the header police. The only thing I haven't seen yet is a rust colored header coating.
Dyno Don is a well respected guy and that many people can't all be wrong. There's a lot involved with header design and it appears that the advantage of these will be their appearance. Certainly Don can make more power with mid-length or long tubes but they would be busted by the EPA folks. Everyone in California should look at these as a potential improvement. There won't be a lot of difference on near stock engines but as the power goes up, so will their performance.
These are a great way to increase power while appearing stock to the header police. The only thing I haven't seen yet is a rust colored header coating.
Dyno Don is a well respected guy and that many people can't all be wrong. There's a lot involved with header design and it appears that the advantage of these will be their appearance. Certainly Don can make more power with mid-length or long tubes but they would be busted by the EPA folks. Everyone in California should look at these as a potential improvement. There won't be a lot of difference on near stock engines but as the power goes up, so will their performance.
Racer
Joined: Oct 2007
Posts: 478
Likes: 1
"Without a CARB certification will these headers pass the Cali emissions inspection? "
They look just like the stock headers. If asked I would just say they were just getting rusty from age and you had them coated for preservation and looks to spruce up the engine compartment. It has been my experience here in California that most techs don't care as along as all the smog equipment is hooked up and works, looks right and blows clean through the sniffer.
I believe Dyno Don can make them up with or without the air tubes. I know he does that with our 3rd Gen cars. So no problem for the back East guys.
They look just like the stock headers. If asked I would just say they were just getting rusty from age and you had them coated for preservation and looks to spruce up the engine compartment. It has been my experience here in California that most techs don't care as along as all the smog equipment is hooked up and works, looks right and blows clean through the sniffer.
I believe Dyno Don can make them up with or without the air tubes. I know he does that with our 3rd Gen cars. So no problem for the back East guys.
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Thread Starter
Racer
Joined: Jun 2006
Posts: 361
Likes: 6
We installed the headers today because yesterday was dedicated to getting TransAm's new top end set-up buttoned up.
The headers went on with no fitment issues. We did have to remove them once to make clearance to get a wrench on the back bolts on both sides. Both sides dropped in from the top and bolted right in. We made spacers for the oil dipstick tube, a/c and alternator bolts and they all bolted in as they did with the stock headers. I didn't have to fight with anything. There is also more room to get the plugs in and out.
Dyno Don then cut the y-pipe at the precats, shortened them and installed a new o2 bung and flanges. The y-pipe looks as stock as it can get. There are no clearance issues.
I took it for a short ride and noticed the difference right away. I stepped on it and the car jumped with no hesitation. It has a more throaty sound and the throttle response is much better. I will post pics tomorrow and will post the dyno results Saturday.
The headers went on with no fitment issues. We did have to remove them once to make clearance to get a wrench on the back bolts on both sides. Both sides dropped in from the top and bolted right in. We made spacers for the oil dipstick tube, a/c and alternator bolts and they all bolted in as they did with the stock headers. I didn't have to fight with anything. There is also more room to get the plugs in and out.
Dyno Don then cut the y-pipe at the precats, shortened them and installed a new o2 bung and flanges. The y-pipe looks as stock as it can get. There are no clearance issues.
I took it for a short ride and noticed the difference right away. I stepped on it and the car jumped with no hesitation. It has a more throaty sound and the throttle response is much better. I will post pics tomorrow and will post the dyno results Saturday.
Drifting
Joined: Oct 2006
Posts: 1,328
Likes: 14
From: Stafford Connecticut
headers
Way to go Corvette40.Can't wait for the pics and dyno numbers .Could you explain more about the spacers and where you had to place them?Thanks
Last edited by steven mack; Nov 16, 2011 at 08:20 AM. Reason: add info
Thread Starter
Racer
Joined: Jun 2006
Posts: 361
Likes: 6
The stock headers have tubes welded to the flange for the bolts. I don't have a set in front of me right now but I'd say they are about 3" long. The two center bolts on the passenger side have studs on the back end of the bolts for the A/C support rod and the oil dipstick hold down. On the drivers side the second header bolt back from the front has a stud on the back end for the alternator support rod. Because these headers, and most others, don't have theses tubes we had to cut tubing in the same length as the stock headers and use longer bolts to bring them out far enough to attach the support rods. I did have to use a different bolt than stock because the header tubing is 1-3/4" and the stock bolt would not clear, but you could grind off the washer on the stock bolt and it should fit. I will post a pic after I go pay my ticket today.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
Hooker Headers shorties (out of production & photo is CFmembers PLRX's)
Looks like the "wheel" is being re-reinvented here - not that that is a bad thing. Anybody who's done more than a few long tube header to exhaust installs knows what the terms "bolt on" mean. Get built, make'em true "bolt ons," post some installed hp/torque numbers and get a smog numbers for them and you'll be golden.
Looks like the "wheel" is being re-reinvented here - not that that is a bad thing. Anybody who's done more than a few long tube header to exhaust installs knows what the terms "bolt on" mean. Get built, make'em true "bolt ons," post some installed hp/torque numbers and get a smog numbers for them and you'll be golden.
Team Owner
Joined: Aug 2005
Posts: 34,988
Likes: 515
From: Riverside County Southern California
Co-winner 2020 C4 of the Year - Modified
2018 Corvette of Year Finalist
2017 C4 of Year
2016 C7 of Year Finalist
St. Jude Donor '09 thru '20
There are no long tubes with CARB number. The only headers with CARB numbers are the shorty headers.
In California, they check your manifolds, your O2 sensors, your fuel cap, carbon canister, vacuum connections, we have the highest SMOG check and perhaps the highest registration in the country. We SMOG every two years.
Last time I smogged Betty Boop, the SMOG dude saw the shorties and ran into the internet to verify the Hookers CARB number. I told the guy "Those are shorty headers, you are wasting your time"
We have a lot of laws, hippies, liberals, crooked politicians, SMOG laws but at least we have a killer weather during this time of the year
Picture taken exclusively for this thread.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
The only thing I haven't seen yet is a rust colored header coating.
There used to be an EO # for some Doug Thorley shorties back in the day for the L98 before they stopped making them. ILl have to dig through the desk and see if I still have it. Copy of the actual badge, too.
Always a way
Even ifyou had to take it to the smog ref bet if all the tubes were in place and appeared stock they would pass it being as replacement manifolds are NLA.
Last edited by cv67; Nov 16, 2011 at 02:00 PM.
Drifting
Joined: Oct 2006
Posts: 1,328
Likes: 14
From: Stafford Connecticut
Not really.Dyno Dons has what would pass as a longer collector and more room for spark plug clearance.The hookers also look like the tubes where they join together on the bottom look like they have the same problem the stock headers have.Not enough room for full 1 3/4's exit for the individual exhaust ports.If you look at Dyno Dons you can see that you will get the full 1 3/4's exit from all ports into the small and extended collector.That should make a big difference in flow.With even some scavenging being accomplished.
Thread Starter
Racer
Joined: Jun 2006
Posts: 361
Likes: 6
Here is the drivers side for comparison. I just changed the alternator from the stock CS-130 to a CS-144 and I haven't fabricated the support rod yet.
Thread Starter
Racer
Joined: Jun 2006
Posts: 361
Likes: 6
Hooker Headers shorties (out of production & photo is CFmembers PLRX's)
Looks like the "wheel" is being re-reinvented here - not that that is a bad thing. Anybody who's done more than a few long tube header to exhaust installs knows what the terms "bolt on" mean. Get built, make'em true "bolt ons," post some installed hp/torque numbers and get a smog numbers for them and you'll be golden.
Looks like the "wheel" is being re-reinvented here - not that that is a bad thing. Anybody who's done more than a few long tube header to exhaust installs knows what the terms "bolt on" mean. Get built, make'em true "bolt ons," post some installed hp/torque numbers and get a smog numbers for them and you'll be golden.
Drifting
Joined: Oct 2006
Posts: 1,328
Likes: 14
From: Stafford Connecticut
headers
Excellent info I was really hoping these would work with straight plugs because that's what I have on my Vette.I had to dimple the heck out of my stock headers to get even the shortest spark plugs to fit.Even then I kept burning my spark plug boots.Man I want a pair of these.
Also thanks for the pics.
Also thanks for the pics.
Last edited by steven mack; Nov 16, 2011 at 03:32 PM. Reason: add info